Brain surgeons have a new way to deliver radiation -- via stamp-sized tiles
[00:00:00] Host Amber Smith: From Upstate Medical University in Syracuse, New York, I'm Amber Smith. This is "HealthLink on Air." Neurosurgeons have a new way to target radiation therapy in patients with brain tumors, and here to talk about this new tool is Dr. Harish Babu, MD, PhD. He's co-director of the brain tumor program at Upstate and director of minimally invasive neurosurgery. Welcome back to "HealthLink on Air," Dr. Babu.
[00:00:25] Harish Babu, MD, PhD: Thank you. It's a pleasure to be on "HealthLink."
[00:00:28] Host Amber Smith: So tell us about this new tool called Gamma Tile.
[00:00:34] Harish Babu, MD, PhD: Gamma Tile is a surgically targeted that radiation therapy technology that has been recently approved by the FDA to be used for brain tumor patients. Usually brain tumors are treated with a combination of surgery and radiation. And, usually that radiation is an external beam. You sit in a radiation machine, and the radiation comes from the outside. This is the other way around. Here, we place the radiation sources inside the brain at the site of surgery. So the radiation happens right the moment after surgery.
[00:01:14] Harish Babu, MD, PhD: Now, these are stamp-sized, bioabsorbable collagen tiles that are embedded with small radiation sources, and they are designed to be implanted by neurosurgeon at the end of a tumor resection. Now these stamp-sized radiation sources are placed at the edge of the resection area where the need for the radiation is the most, because we think that's where most of the cancer cells are and where the boundary between the cancer and the normal brain is.
[00:01:48] Host Amber Smith: Let me just interrupt you. So it goes into the space that's left after you take the tumor out, and you said it's a stamp-sized tile. Is one tile all that you need?
[00:02:01] Harish Babu, MD, PhD: The number of tiles that we need may differ depending upon each patient's tumor, the surgery and the resection cavity, or the resection bed that is left after removal of the tumor. So this is decided on an individual basis for an individual patient. There is no standard number.
[00:02:23] Host Amber Smith: You described it as a bio resorbable, collagen tile. Does that mean it dissolves into the tissue or what happens to it once you leave it there?
[00:02:34] Harish Babu, MD, PhD: The collagen structure which holds these radiation sources are implanted, but eventually these collagen sources are absorbed by the brain tissue, usually within three, four months after implant. Now the tiles hold their shape and the position within the brain, while the radiation is being delivered. But after about three, four months, these collagen tiles are dissolved, and only this loose sort of small seeds of this radiation are left and, and the radiation has also decreased. And, those radiation seeds stay there, but the larger tile just dissolves.
[00:03:18] Host Amber Smith: When I looked for some pictures online, these little tiles had sort of bumps on one side of them, almost like a Lego tile. Why are they designed with bumps on one side?
[00:03:33] Harish Babu, MD, PhD: It is to some extent that is to let the surgeons know which side to place should go to the brain side and which side should be to sort of the cavity side. The bumpy side of the tile goes toward the brain side, and it is designed in such a way that the bumpy side would give the correct dose of radiation, the amount of radiation, so that, that helps us place those tiles during surgery appropriately.
[00:04:06] Host Amber Smith: I've heard of brachytherapy where radiation sources are placed in the tumor resection cavity during surgery. How is this different?
[00:04:15] Harish Babu, MD, PhD: Brachytherapies have been tried for a long time. In fact, I think the first ones were tried back in 1930s, 1940s, and several different sources of radiation have evolved over a period of time. And, at least about 20 years ago, 30 years ago, what was being tried was iodine 125. Now, in the past 20 years or so radiation scientists, physicists have seen that cesium 131 is, is a much better source for radiation. It gives about the same radiation, it is effective, but it has one advantage: that is, it is a shorter half-life. You get the same amount of radiation in a shorter time period and in a shorter distance. From a medicine point of view, that translates to, you get treated for a shorter period of time. There is improved ease of use, and it increases efficacy. It also has a superior safety profile. So in some sense, this is similar to the brachytherapy, but a lot more evolved and technologically better.
[00:05:29] Host Amber Smith: How does treatment using Gamma Tile compare with standard radiation treatment?
[00:05:37] Harish Babu, MD, PhD: These gamma tiles, these radiation sources, spit out radiation, and that affects the cancer cells. Now, when you place this gamma tiles, about 50% of the therapeutic dose is delivered within the first 10 days after surgery. Now in external beam radiation, everyday you would have to go to the the physician's office to get the radiation. And that happens over a period of days and weeks. Here, 50% of the dose is delivered within the first 10 days. In fact, about 95% of the dose is delivered within the six weeks, and you don't have to go to any physician's office. You are up and about, doing daily things. The radiation is happening inside your brain, and you're not going to any physician's office.
[00:06:34] Host Amber Smith: What are the side effects like, comparing Gamma Tile with the external beam radiation?
[00:06:41] Harish Babu, MD, PhD: So if we start off with the external beam radiation, the side effects are headaches, you have hair loss, nausea, vomiting, tiredness, and you also notice skin and scalp discoloration, and also there is also memory and cognitive problems. Now that doesn't mean that everybody gets this. It's a combination of things that people may get doing, external beam radiation.
[00:07:11] Harish Babu, MD, PhD: Now while in Gamma Tile, there is very little side effect. Sometimes the side effects are related to the radiation necrosis that happens very rarely, but generally it is much more tolerated than the conventional external beam radiation that is designed for classical brain tumors.
[00:07:36] Host Amber Smith: Do we know yet whether Gamma Tile will be more effective at preventing a tumor from growing back then traditional radiation?
[00:07:45] Harish Babu, MD, PhD: We do not know that yet. We don't have enough studies to suggest whether a Gamma Tile is better than the standard radiation therapy. Studies are ongoing. We don't have enough numbers to state that yet.
[00:08:02] Host Amber Smith: You're listening to Upstate's "HealthLink on Air." I'm your host, Amber Smith talking with neurosurgeon, Dr. Harish Babu about a new tool for brain tumors called Gamma Tile. So I want to ask you about what patients may be candidates for the Gamma Tile. Is this for adults, children?
[00:08:19] Harish Babu, MD, PhD: Currently it is FDA approved for adults, for recurrent brain tumors, such as glioblastomas, for metastatic disease and meningiomas, and it is also, since the beginning of 2020, also been approved for primary brain tumors. That is, first time diagnosed brain tumors, but only for adults.
[00:08:42] Host Amber Smith: Does it matter the size of the tumor or where it's located in the brain as to whether they would be a good candidate for this?
[00:08:49] Harish Babu, MD, PhD: As far as size or the location, it is not a concern. Any location or any size patients with tumors can get Gamma Tiles. The only thing is that they should be ready for surgery. Gamma Tiles are placed after surgery, so you need to be a surgical candidate for those tumors. And once at the end of the surgery is when we place these Gamma Tiles. But to answer your question, size and location of the tumor not a concern.
[00:09:24] Host Amber Smith: Is there anything that would disqualify a person from having Gamma Tile? I saw something about hypersensitivity to bovine derived materials.
[00:09:36] Harish Babu, MD, PhD: Because these collagen fibers are derived from bovine material, anybody who has previously had a sensitivity or hypersensitivity to bovine-derived material, they would not be candidates for Gamma Tile. And also if there are any patients who have barely shown to have increased necrosis from radiation, we may also need to counsel them appropriately. They may be sensitive to radiation, as well.
[00:10:07] Host Amber Smith: Now, if someone is going to need to have chemotherapy after the surgery and the Gamma Tile, can they do that with the Gamma Tiles in place?
[00:10:18] Harish Babu, MD, PhD: Certainly they can. Gamma Tile does not exclude any patients from getting chemotherapy. The chemotherapy can continue, just about the same way as they would be conventionally.
[00:10:33] Host Amber Smith: Now will someone who has gamma tile, are they going to be radioactive for a period of time? And can they be around their loved ones in the days after this?
[00:10:44] Harish Babu, MD, PhD: So once we place the gamma tiles, as I just alluded earlier, about 50% of the radiation does happen in the first 10 days, and about 95% of the radiation is in the first six weeks. So during this time, theoretically, there is radioactivity. But we know that the cesium source, the drop-off of the radiation is fairly quick, which means the distance where you feel the radiation is very short, within millimeters. So theoretically, yes one should be aware of this and their loved ones should be counseled that there is radiation within the brain of the patient. But after about six weeks, as I said, 95% of the radiation is gone. So, the first six weeks, one should be aware of this and be careful.
[00:11:41] Host Amber Smith: Well, I'd like to have you walk us through what a patient who's going to have this procedure can expect. So how do you tell someone to prepare in the days ahead of surgery? What do they need to do to get ready?
[00:11:54] Harish Babu, MD, PhD: So placing a Gamma Tile of the Gamma Tile procedure, per se, adds about two or three minutes, in addition to the routine surgery they might otherwise be signing up for. And for any neurosurgical procedure, we sit down with the patient, we talk to them, we counsel them. What are the goals of the surgery? What are we trying here? And what are the risks for surgery? And the risks for surgeries are long, but most importantly, having stroke or coma or serious neurological deficit. We talk to them, depending upon the location and the size of the tumor. And once we have had a discussion, the patient can choose to go with surgery or decide against surgery. And at that time we would, again, discuss what exactly the surgery looks like, where the incision would be, what times and how long will they be in the hospital. Typically after a procedure like this, they would be a night or two nights in the hospital. And, we would say that about the first five to six weeks, they would not have normal activity, just because they would be lethargic, they would be a little weak, just from getting the surgery. After that, they can go about doing their normal day-to-day activities.
[00:13:26] Host Amber Smith: So it sounds like inserting the Gamma Tile only adds, you said two or three minutes at the end of the procedure, and having these installed doesn't seem like it changes the course of recovery for most people. Is that right?
[00:13:41] Harish Babu, MD, PhD: Correct. Yeah. From a surgeon's standpoint, it's about two to three minutes extra for the surgery. And from patient's perspective, it shouldn't change anything more than the normal surgery as well. Obviously this sometimes may depend upon patient to patient, but most patients have done very well with Gamma Tile placement.
[00:14:01] Host Amber Smith: Will the remnants of the Gamma Tile show up on brain scans in the future that they have?
[00:14:06] Harish Babu, MD, PhD: As I said, the bioabsorbable collagen tiles are absorbed in three to four months, so they don't show up. But the seeds are these two- to three-millimeter size titanium beads, they will show up on the scan, even after the radiation sources have depleted and even after the collagen has been absorbed. So yes, those radiation seeds will show up on the MRI.
[00:14:38] Host Amber Smith: Now for listeners who want to learn more about Gamma Tile, how can they find out or get connected with you if this is something that interests them?
[00:14:47] Harish Babu, MD, PhD: The patients or referring positions who may be interested in Gamma Tile, they certainly can, can, you know, uh, sort of seek a referral at the department of neurosurgery.
[00:15:02] Harish Babu, MD, PhD: Uh, they can either send us a referral. Our office will be happy to contact them and channel them to the appropriate surgical field
[00:15:14] Host Amber Smith: I'll let listeners know that phone number for the neurosurgery department: 3 1 5- 4 6 4 -4 4 7 0. Thank you to Dr. Harish Babu. He's co-director of the brain tumor program at Upstate and director of minimally invasive neurosurgery, and we've been talking about the new Gamma Tile. I'm Amber Smith for Upstate's podcast and radio talk show "HealthLink on Air."